In wireless networks, there is no global clock. Each wireless system, or wireless node, has its own internal clock and its own notion of time. These clocks can easily drift anywhere from microseconds to seconds in a small duration of time, accumulating significant errors over time. These clock drifts potentially pose serious problems to applications that depend on a synchronized notion of time. For most applications and algorithms that run in a distributed wireless system, time information is needed. For example, in a distributed wireless system the time, time-of-day, etc. of when an event will happen on a wireless node in the network may be required. Also, the time interval between two events that happened on different wireless nodes in the network or the relative ordering of events that happened on different wireless nodes in the network may need to be known.
In ad-hoc wireless networks such as sensor networks, many applications may need for the local clocks of the sensor nodes to be synchronized, requiring various degree of precision to coordinate their operations and collaborate to achieve complex sensing tasks. Data fusion is an example of such coordination in which data collected at different nodes are aggregated into a meaningful result.
Furthermore, time alignment is critical for ensuring quality of service (QoS) for sensors network applications such as data, voice and video over a wireless access medium. As wireless networks evolve to packet switching, proper and precision time synchronization is needed for IP networks to achieve performance quality. Accurate time alignment (Time-transfer or time-of-day) is needed to support QoS and traffic engineering.
Therefore, it would be desirable to provide a system and method that overcomes the above.